+#ifdef CONFIG_USB_EHCI_TT_NEWSCHED
+
+/* Which uframe does the low/fullspeed transfer start in?
+ *
+ * The parameter is the mask of ssplits in "H-frame" terms
+ * and this returns the transfer start uframe in "B-frame" terms,
+ * which allows both to match, e.g. a ssplit in "H-frame" uframe 0
+ * will cause a transfer in "B-frame" uframe 0. "B-frames" lag
+ * "H-frames" by 1 uframe. See the EHCI spec sec 4.5 and figure 4.7.
+ */
+static inline unsigned char tt_start_uframe(struct ehci_hcd *ehci, __le32 mask)
+{
+ unsigned char smask = QH_SMASK & le32_to_cpu(mask);
+ if (!smask) {
+ ehci_err(ehci, "invalid empty smask!\n");
+ /* uframe 7 can't have bw so this will indicate failure */
+ return 7;
+ }
+ return ffs(smask) - 1;
+}
+
+static const unsigned char
+max_tt_usecs[] = { 125, 125, 125, 125, 125, 125, 30, 0 };
+
+/* carryover low/fullspeed bandwidth that crosses uframe boundries */
+static inline void carryover_tt_bandwidth(unsigned short tt_usecs[8])
+{
+ int i;
+ for (i=0; i<7; i++) {
+ if (max_tt_usecs[i] < tt_usecs[i]) {
+ tt_usecs[i+1] += tt_usecs[i] - max_tt_usecs[i];
+ tt_usecs[i] = max_tt_usecs[i];
+ }
+ }
+}
+
+/* How many of the tt's periodic downstream 1000 usecs are allocated?
+ *
+ * While this measures the bandwidth in terms of usecs/uframe,
+ * the low/fullspeed bus has no notion of uframes, so any particular
+ * low/fullspeed transfer can "carry over" from one uframe to the next,
+ * since the TT just performs downstream transfers in sequence.
+ *
+ * For example two seperate 100 usec transfers can start in the same uframe,
+ * and the second one would "carry over" 75 usecs into the next uframe.
+ */
+static void
+periodic_tt_usecs (
+ struct ehci_hcd *ehci,
+ struct usb_device *dev,
+ unsigned frame,
+ unsigned short tt_usecs[8]
+)
+{
+ __le32 *hw_p = &ehci->periodic [frame];
+ union ehci_shadow *q = &ehci->pshadow [frame];
+ unsigned char uf;
+
+ memset(tt_usecs, 0, 16);
+
+ while (q->ptr) {
+ switch (Q_NEXT_TYPE(*hw_p)) {
+ case Q_TYPE_ITD:
+ hw_p = &q->itd->hw_next;
+ q = &q->itd->itd_next;
+ continue;
+ case Q_TYPE_QH:
+ if (same_tt(dev, q->qh->dev)) {
+ uf = tt_start_uframe(ehci, q->qh->hw_info2);
+ tt_usecs[uf] += q->qh->tt_usecs;
+ }
+ hw_p = &q->qh->hw_next;
+ q = &q->qh->qh_next;
+ continue;
+ case Q_TYPE_SITD:
+ if (same_tt(dev, q->sitd->urb->dev)) {
+ uf = tt_start_uframe(ehci, q->sitd->hw_uframe);
+ tt_usecs[uf] += q->sitd->stream->tt_usecs;
+ }
+ hw_p = &q->sitd->hw_next;
+ q = &q->sitd->sitd_next;
+ continue;
+ // case Q_TYPE_FSTN:
+ default:
+ ehci_dbg(ehci,
+ "ignoring periodic frame %d FSTN\n", frame);
+ hw_p = &q->fstn->hw_next;
+ q = &q->fstn->fstn_next;
+ }
+ }
+
+ carryover_tt_bandwidth(tt_usecs);
+
+ if (max_tt_usecs[7] < tt_usecs[7])
+ ehci_err(ehci, "frame %d tt sched overrun: %d usecs\n",
+ frame, tt_usecs[7] - max_tt_usecs[7]);
+}
+
+/*
+ * Return true if the device's tt's downstream bus is available for a
+ * periodic transfer of the specified length (usecs), starting at the
+ * specified frame/uframe. Note that (as summarized in section 11.19
+ * of the usb 2.0 spec) TTs can buffer multiple transactions for each
+ * uframe.
+ *
+ * The uframe parameter is when the fullspeed/lowspeed transfer
+ * should be executed in "B-frame" terms, which is the same as the
+ * highspeed ssplit's uframe (which is in "H-frame" terms). For example
+ * a ssplit in "H-frame" 0 causes a transfer in "B-frame" 0.
+ * See the EHCI spec sec 4.5 and fig 4.7.
+ *
+ * This checks if the full/lowspeed bus, at the specified starting uframe,
+ * has the specified bandwidth available, according to rules listed
+ * in USB 2.0 spec section 11.18.1 fig 11-60.
+ *
+ * This does not check if the transfer would exceed the max ssplit
+ * limit of 16, specified in USB 2.0 spec section 11.18.4 requirement #4,
+ * since proper scheduling limits ssplits to less than 16 per uframe.
+ */
+static int tt_available (
+ struct ehci_hcd *ehci,
+ unsigned period,
+ struct usb_device *dev,
+ unsigned frame,
+ unsigned uframe,
+ u16 usecs
+)
+{
+ if ((period == 0) || (uframe >= 7)) /* error */
+ return 0;
+
+ for (; frame < ehci->periodic_size; frame += period) {
+ unsigned short tt_usecs[8];
+
+ periodic_tt_usecs (ehci, dev, frame, tt_usecs);
+
+ ehci_vdbg(ehci, "tt frame %d check %d usecs start uframe %d in"
+ " schedule %d/%d/%d/%d/%d/%d/%d/%d\n",
+ frame, usecs, uframe,
+ tt_usecs[0], tt_usecs[1], tt_usecs[2], tt_usecs[3],
+ tt_usecs[4], tt_usecs[5], tt_usecs[6], tt_usecs[7]);
+
+ if (max_tt_usecs[uframe] <= tt_usecs[uframe]) {
+ ehci_vdbg(ehci, "frame %d uframe %d fully scheduled\n",
+ frame, uframe);
+ return 0;
+ }
+
+ /* special case for isoc transfers larger than 125us:
+ * the first and each subsequent fully used uframe
+ * must be empty, so as to not illegally delay
+ * already scheduled transactions
+ */
+ if (125 < usecs) {
+ int ufs = (usecs / 125) - 1;
+ int i;
+ for (i = uframe; i < (uframe + ufs) && i < 8; i++)
+ if (0 < tt_usecs[i]) {
+ ehci_vdbg(ehci,
+ "multi-uframe xfer can't fit "
+ "in frame %d uframe %d\n",
+ frame, i);
+ return 0;
+ }
+ }
+
+ tt_usecs[uframe] += usecs;
+
+ carryover_tt_bandwidth(tt_usecs);
+
+ /* fail if the carryover pushed bw past the last uframe's limit */
+ if (max_tt_usecs[7] < tt_usecs[7]) {
+ ehci_vdbg(ehci,
+ "tt unavailable usecs %d frame %d uframe %d\n",
+ usecs, frame, uframe);
+ return 0;
+ }
+ }
+
+ return 1;
+}
+
+#else
+